The least economical way of driving a car is to use full throttle all the time and rev the engine to its maximum speed in every gear. It follows that gentler use of the accelerator means that you drive more economically. It is still possible to make good progress even if you never use more than half of the accelerator pedal travel - you will simply take slightly longer to reach your intended cruising speed.

When a car is travelling at a constant speed along a level road, most of the power of the engine is used to overcome aerodynamic resistance. Cars with more "slippery" shapes can therefore cruise with less fuel. There isn't much you can do about the shape of your car, but the same effect means that open windows or sunroofs - which create aerodynamic drag - will also make the car less economical.

So will anything that uses extra power. Lights, windscreen wipers, air-conditioning, audio systems and heated rear windows all require power to varying degrees, and all affect fuel economy, which is why they are all switched off during the official fuel economy tests.

Those tests give nothing more than a comparitive guide to fuel economy, and you can't rely on the fact that a car gets 32.4mpg in the official test will do 32.4 miles for every gallon of fuel you use. More information on this can be found in our fuel economy testing feature.

The most efficient range of engine speeds depends very much on the individual car, but a good guide is that a petrol-engined car will operate economically between 2000 and 4000rpm, while a turbo diesel will do so between 1500 and 2500rpm.

Back to Driving Tips index